Which of the following led to increased tension between the United States and Japan in 1937?

The Nanjing Massacre occurred in 1937, when Japanese forces captured Nanjing and carried out widespread killings and other atrocities. News of the violence increased anger and tension between the United States and Japan. Roosevelt’s Four Freedoms speech and the Lend-Lease Act came later, while Japan’s oil exports were not the key 1937 event.

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